62 PIOTOniAL FRAG TIG AL VEGETABLE GnOWING. 



Phytoplithora infestans, has gone for ever, but a wet one dispels the 

 sweet dream. 



Potatoes are subject to several enemies, and the crop is of such 

 importance that a little attention may well be devoted to each. 



Blight or Murrain. — This, Phytophthora, once called Peronospora, 

 infestans, which first made itself formidable in the closing years of the 

 first half of the nineteenth century, is essentially a child of moisture. 

 It is rarely that one sees more than a casual trace or two of it in dry, 

 warm summers, though it is not often completely absent from a large 

 collection of varieties. I usually grow from fifty to seventy sorts, and 

 I cannot remember the season w^hen a plant here and there did not 

 show signs of a slight infestation. This is a small matter, and really 

 it serves a good purpose, for it reminds the grower that his enemy 

 lives on, and that he must not be lulled into a false security. In wet 

 seasons, or during cold, humid spells, the disease is on quite a 

 different footing, and often spoils the crop. The brown patches 

 under the leaf, the musty smell, the collapsing foliage, all tell their 

 story. Potato growers now have a valuable remedy at their 

 command, and if only they will look a little ahead, have their 

 materials ready, and keep an intelligent watch on the weather, they 

 need suffer little loss. I have proved the efficacy of Bordeaux 

 Mixture, and now, with a small addition of my own, am always 

 ready to take the field with confidence. Bordeaux Mixture as made 

 by me consists of : — 



1 lb. sulphate of copper (bluestone) \ in 10 gallons of water. (1 lb. of 

 1 lb. freshly slacked Kme > cheap treacle is sometimes sub- 



J lb. soft soap j stituted for the soft soap. ) 



The bluestone. which may cost about 4d. per lb., is first dissolved in a 

 little hot water in a wooden bucket, then the lime is stirred up into 

 another vessel of water ; finally the two are poured together, and the 

 soft soap, churned up in a little hot water, is poured in. The stuff 

 may be put on with a knapsack sprayer, or Abol syringe, and in 

 order to get it well on to the under surface of the leaves, there should 

 be two operators, one to hold back a line of tops with a Bean pole, 

 the other to do the spraying. The grower should be on the watch 

 in July and onwards. If continued heavy rains wash the deposit 

 off the leaves, he must go to work again and repeat the dressing. 



The following cultural points are worth observing : (1) Select 

 well-drained soil if possible. (2) Ensure a strong, healthy plant by 

 using good seed and practising sound culture. (3) Plant in wide 

 ranks so as to allow of plenty of soil for earthing. (4) In moulding 

 up, do it thoroughly and finish the ridges sharply, dusting lime on them 

 if the weather turn muggy in July and August. (6) Whatever show 

 sorts may be grown, take care to include one or two tough disease 

 resisters, such as Magnum Bonum and ]Main Crop. 



Curl in the Leaf. — In the early part of 1900 Potato growers in 

 most parts of Great Britain observed that their plants developed 

 slowly, and that the foliage, which was very scanty, curled, without 

 losing its colour. Large numbers of plants never made progress, but 



